Trimming mechanism for sewing machines



J. c. RINGE TRIMMING MECHANISM FOR SEWING MACHINES 'May 25, 1926.

Filed Oct. 7, 1924 2 Sheets-Sheet 1 mvENToR t/olz (fzlye BY ATToRNEY May 25, 1926.

J. c. RINGE TRIMMING MECHANISMFOR SEWING MACHINES l Filed 00t- 7, 1.924 2 sheetsl-Shlet 2 INVENroR L/o 'A ToRNEY liatente'd May 25, 1926.

UNITED lSTATES PATENT GFFICE.

JOHN C. RINGE, F STRATFORD, CONNECTICUT, ASSIGNOR/TO THE SINGER MANUFAC- TURING COMPANY, 0F ELIZABETH, EW JERSEY, A. CORPORATION 0F NEW JERSEY.

TRIMMING MECHANISM FOR SEWING' MACHINES.

Application filed October 7, 1924; Serial No. 742,095.

This invention relates to improvements in that class of sewing machine trimmers more y particularly adapted to trim 0H the edge of the lower of two pieces of material during l the stitching operation, and in which a knife is carried.. by a horizontally swinging arm. An object of the present invention is to prolvide a simple and effective trimmer of the class referred to, adapted to be used in connection with a sewin machine having a work-support comprising a vertically extending post. j

Another object of the invention is to provide a trimming mechanism of the class referred to for a post machine, which may be readily thrown into and out of operal tion during the operation of the machine.

A further object of the inventionh is to provide an improved form of edge-guide for use in combination with a horizontally swinging trimmer in a post machine.

The improved trimmer comprises a bladecarrying arm extending laterally lfrom the upper end of a vertical rock-shaft, disposed adjacent the work-supporting post and journaled for oscillation in bearing-brackets projecting therefrom. To actuate the trimmerblade there is clamped upon the rock-shaft, adjacent its lowerfend, an arm which is releasably latched with an actuating arm pivotally mounted on the rock-shaft and having a depending fork straddling an eccentric on the usual loop-taker actuating shaft below the bed-plate of they machine. A torsiony spring surrounding the rock-shaft functions to throw the trimmer-blade into a lpredetermined inoperative position when the actuating arm is released from the rock-shaft.

An edge-guide for the work overlies the trimmer-blade and is adjustably secured upon an arm pivotally mounted upon the upper bearing-bracket of the rock-shaft for swinging movements about a horizontal axis into and out of operative position. The operative position of the edge-guide is determined by the engagement of its carrying arm with a limit-screw, said edge-guide being frictionally held4 in any position into which it may beswung.

In theV accompanying drawings, Fig. 1 is a side elevation, partly in section, of a portion of a post sewing machine]` embodying the present improvements. Fig. 2 isza front end elevation of a part of the work-supporting post and showing the needle and presserbars. Fig. 3 is a top-plan view of a art of the bed and post. Fig. 4 is a sectinal view vsubstantially on the line of Fig.

3. Fig. 5 is a perspective p view of a portion of the trlmming knife.

l Referring to the drawings, the sewing mav present improvement has from which rises the vertical workf thread-mass carrying loop-taker 7. 'Operai tively disposed withln the post 2 is a feedbar 8 which may be actuated in any suitable and well known manner, said feed-bar carrying at its upper end a feed-dog 9 which is adapt-ed to operate in a slot 10 provided in a throat-plate .11 secured by screws as 12 upon-the upper end of the'post 2. Opposed to the feed-dog is a roller-presser 13 carried by a presser-bar 14 suitably mounted in the head of the usual overhanging bracket-arm (not shown) ofthe machine, while adjacent to said presser-bar is disposed a needle-bar 15 carrying a needle 16. All of the described parts are well known in a sewing machine having a vertical work-supporting postl andit is therefore deemed unessenti al to illustrate and describe the same in detail.

Referring now more particularly to the present improved trimming mechanism, the

work supporting post 2 is provided at its upper end-with a laterally projecting lug 17 and adjacent its lower end with a pair of lateral lugs, as `18, .which lugs are formed with alined apertures to provide bearings for a vertical trimmer-shaft 19. Above the lug 17, the trimmer-shaft 19 is provided with a head 20, upon which is secured by screws,

as 21, a horizontally vibrating trimmerblade carrier 22. Secured by screws, as 23, upon the'under side of the carrier 22 is the shank 24 of a trimmer-blade having the usual depending lip25 terminating in a cutting edge 26. The forward corner 27 of the trimmer-blade is preferably upturned to facilitate the passage thereunder of one ply of the work. The depending lip 25 of the trimmer-blade is disposed in a recess 28 provided in the throat-plate 11 by `cutting away andtlience downwardly, being formed at its free end with a socketed boss 33' in which is slidingly disposed a latch-plunger 34 depressed by a spring 35 within the boss33. The downward movement of the plunger under the action of thespring 35 is limited by the engagement of a head 36 of the plunger with the bo-ss 33. An actuating arm 37 is mounted upon the shaft 19 for pivotal movement relatively thereto, i. e., it is loosely clamped upon said shaft by a screw 38. The free end of the arm 37 is provided with an aperture 39 adapted to receive the plunger 34 whereby in the operative position of the trimmer-blade the two arms vibrate in unison. To vibrate the actuating arm 37 it carries a depending fork 40, straddling an eccentric 41 provided upon the loop-taker actuating shaft 3 and extending through a slot 42 formed in the fra-me.

It is apparent from the foregoing description that when the two arms 31 and 37 are latched by the plunger 34 for unison vibration, the eccentric 41 will cause rock- `ing movements of the vertical shaft 19 whereby the trimmer-blade is vibrated to sever the work. Means are, however, provided for at will disconnectin the trimmerblade from its actuating mec anism and to simultaneously throw said blade into an inoperative position. To this end, a releaselever 43, 44 is pivotally mounted upon' a pivot-pin 45 on the free end-of the actuating arm 37 one arm 43 of said lever constituting a thumb-piece for convenient manipulation thereof and the other arm 44 being curved upwardly to enter the latchaperture 39 and engage the lower end of the plunger 34. By depressing the -arm 43 of the release-lever, the plunger 34 is lifted out of the aperture 39, whereupon a coilspring 46 surrounding the vertical roekshaft 19 acts to impart to said rock-shaft a greater extent of movement than its normal or operating retractive movement, thereby throwing the trimmer-blade into the inoperative position indicated by dotted lines in Fig. 3. KThis inoperative position of the trimmer-blade is determined by the engagement of the arm.,31 with a somewhat resilient lateral ear 47 of a stop-bracket 48 secured by screws as 49 (only one of which is shown) upon a cover-plate 50. The

cover-plate 50 is secured by screws, as 51,y

ing position of the plunger is approXi` mately determined by the lug 52.

The work-severing action of the trimmerblade is the same as heretofore in underedge trimmers of this class and is so well known that it is not deemed-necessary to herein describe the same in detail, the present invention residing more particularly in the supporting and actuating mechanism therefor as applied to a post machine. As usual, there is provided Aan edge-guide 54 for the upper ply of the work, which guide overlies the trimmer-blade. In the present instance, however, the shank of the edge-guide 54 is adjustably secured by screws as 55 upon an arm 56 which curves upwardly over the front edge of the blade-carrier 22 and is pivotally supported by a screw 57 threaded into the upper bearing-lug 17. lA frictionwasher 58 interposed between the head of the 'screw 57 and the arm 56 retains said arm in any position into which it may be swung, the movement ofsaid arm into the operative position of the guide being checked by the engagement of a notch 59 in said arm with a stationary limit-screw 60.

Having thus set forth the nature gf the invention, what I claim herein is 1. Ina sewing machine, the combination with a supporting-frame and a work-supporting post projecting vertically therefrom,

mer-blade carrier extending laterally froml said rock-shaft, a trimmer-blade carried thereby, and means for oscillating said rockshaft to actuate the trimmer-blade.

3. In a sewing machinefthe combination with a supporting-frame, and a work-supporting post projecting vertically therefrom, of a horizontally vibrating trimmer-blade disposed above said post, a vertical trimmer-blade carrying rock-shaft journaled in said post, a vibratory arm projecting laterally from said rock-shaft, an actuating arm pivoted coaxially with said rock-shaft, means for vibrating said actuating arm, and an operative connection between said arms releasable during the operation of the machine. v

4. In a sewing machine, the combination with a supporting-frame, and a work-supporting post projecting vertically therefrom, of a horizontally vibrating trimmer-blade disposed above said post, a vertical trimmer-blade carrying rock-shaft, a vibratory arm projecting laterally from said rockshaft, an actuating arm pivotedv coaxially with said rock-shaft, means for vibrating said actuating arm, an operative connection between said arms releasable during the operation of the machine, and a spring for throwing said trimmer-blade out of operative position upon release of said connection.

5. In a sewing machine, the combination with a supporting-frame, and a work-supporting post projecting vertically therefrom, of a horizontally vibrating trimmer-blade disposed above said post, a vertical trimmerblade carrying rock-shaft, a vibratory arm projecting laterally from said rock-shaft, an actuating arm pivoted coaXially with said rock-shaft, means for vibratingvsaid actuating arm, an operative connection between said arms releasable during the operation of the machine, a coil-spring surrounding said rock-shaft for throwing said trimmer-blade out of operative position upon release of said connection, and a stop for determining the inoperative position of said blade.

6. In a sewing machine having a supporting-frame, in combination, a vertically ldisposed rock-shaft journaled in said frame, a trimmer-blade carrier operatively connected with said rock-shaft, a vibratory arm projecting laterally from said rock-shaft for movement therewith, an actuating arm, one of said arms being provided with a springpressed plunger and the other arm with a latching aperture for reception of said plunger, means for releasing the plunger plunger provided on said vibratory arm adapted to enter said aperture to operatively connect said arms, a plunger release-lever carried by. said actuating arm, and means for vibrating the actuating arm.

8. In a sewing machine having a supporting-frame provided with a vertical work-supporting post, in combination, a vertical rock-shaft disposed adjacent said post, a horizontally vibrating trimmerblade carrier fixed upon said rock-shaft, a vibrating arm projecting from said rockshaft for movement therewith, an actuating arm capable of vibratory movements independently of said rock-shaft, a latching connection between said arms to compel vibration thereof in unison, means for at will releasing saidlatching connection, a housing for the actuating arm, and a stop-lug for said actuating arm provided? upon said housing.

9. In a sewing machine having a supporting-frameprovi'ded with a vertical worksupporting post, in combination, a horizontally vibrating trimmer-blade disposed above said post, a trimmer-blade carrier, means for actuating said carrier, an edgeguide overlying said trimmer-blade, an edge-guide carrying arm supported by said post for pivotal `movement about a sbstantially horizontal axis, and means for .txedly determining the operative position of said edge-guide.

In testimony whereof, Ifhave signed my name to this specification.

JOHN C. RINGE. 

